Flotation, which is a physical pretreatment method, is used to separate the graphite particles in the BM based on their wettability properties. Chemical and thermal procedures can be employed separately to remove binders and facilitate BM particle separation. According to the literature, thermal pretreatment at 500–600 ℃ can be used to evaporate organic materials in BM (e.g., electrolyte, separator, and PVDF residuals) that contain F, which is known as a hazardous and corrosive element. The process for recycling of BM typically starts with a pretreatment process, to liberate the battery components, and enhance the efficiency of target elements recovery. The BM contains anode materials (mainly graphite), cathode materials (e.g., LiMeO 2), binders (usually polyvinylidene fluoride (PVDF)), conductive additives (acetylene black), traces of electrolyte (typically Li salt dissolved in an organic solvent), and electrode current collector residuals (Cu and Al). This generates plastic and metallic streams, which can be recycled directly by physical separation, leaving behind a small particle size fraction, known as black mass (BM). Īfter their EOL, LIBs are mechanically collected, discharged, and disintegrated. The use of eco-friendly and resource-efficient methods for handling LIB components after EOL relieves environmental contamination pressure, generates remarkable economic and social benefits, and reduces the dependency on primary materials. The regulation states that the recycling efficiency of LIBs should exceed 65% by 2025. In the regulatory proposal concerning batteries and waste batteries published by the European Commission, special attention should be given to recycling of end-of-life (EOL) batteries and closing the material loops. By 2025, it is expected that ⁓ 850,000 tons of LIBs will need to be recycled globally. It is predicted that the number of electric vehicles will increase from 4 million in 2018 to 900 million in 2048. Due to the increasing demand in fossil-free energy, a large amount of LIBs is produced today. Since the beginning of the 1990s, Li-ion batteries (LIBs) have been regarded as the most promising energy storage solution for various applications due to their high energy density, low memory effect, low self-discharge, and long lifespan. Regarding the Li behavior, it was observed that in the presence of Al, AlLiO 2 is the most likely composition to form, and it changes to LiF by increasing the F concentration in the composition. As the products of this process, metallic Co and Ni phases were formed, and part of the graphite remained unreacted. The Li-metal oxide was partially reduced to lower oxides and Li carbonate at ⁓ 600 ℃, and the main mass loss was caused by carbothermic reduction immediately thereafter. When the BM was thermally treated, the binders decomposed until a temperature of 500 ℃ was reached, where the volatilization of hydrocarbons was observed, although F mostly persisted in the BM. The analyses demonstrate that the mineralogical and morphological properties of the two fractions do not significantly differ, while the amounts of C and organic materials might vary. The thermal behavior of the BM is studied with thermal analysis techniques. In this study, two types of BM are characterized in two fractions of 150–700 µm and smaller than 150 µm. Pyrometallurgy is a route known for recycling of BM, in which identifying the BM’s behavior at high temperatures is essential. BM is composed mainly of graphite and Li-metal complex oxides. After their end-of-life, the batteries are collected, discharged, and mechanically disintegrated, generating plastic and metallic streams that are recycled directly this leaves behind a small particle size fraction known as black mass (BM). The increased demand for Li-ion batteries has prompted the scientific community to improve recycling routes in order to reuse the valuable materials in batteries.
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